Cardiac arrhythmias are responsible for 250,000 sudden deaths per year in the United States. Despite their importance, prior to this study there was little known about the underlying disease mechanisms, many of which proved to be inherited. Dr. Keating's studies are aimed at defining the genes that contribute to susceptibility to cardiac arrhythmias. He has focused on the long QT syndrome (LQT) and idiopathic ventricular fibrillation (IVF). These are inherited disorders that cause sudden death from unpredictable, episodic ventricular arrhythmias. Pedigrees are carefully phenotyped, and linkage analyses are then carried out to map and then clone arrhythmia susceptibility genes. Dr. Keating's studies have now been expanded to include genes responsible for inherited forms of heart failure (the inherited cardiomyopathies).